Group: U.S. not protected against mad cowLIBBY QUAIDAssociated PressWASHINGTON - Researchers and the nation's No. 1 burger seller say the government is not fully protecting animals or people from mad cow disease.

Stronger steps are needed to keep infection from entering the food chain for cattle, the critics wrote in comments to the Food and Drug Administration.

The group includes McDonald's Corp., seven scientists and experts and a pharmaceutical supplier, Serologicals Corp.

The government proposed new safeguards two months ago, but researchers said that effort "falls woefully short" and would continue to let cattle eat potentially infected feed, the primary way mad cow disease is spread.

"We do not feel that we can overstate the dangers from the insidious threat from these diseases and the need to control and arrest them to prevent any possibility of spread," the researchers wrote.

McDonald's said the risk of exposure to the disease should be reduced to zero, or as close as possible. "It is our opinion that the government can take further action to reduce this risk," wrote company Vice President Dick Crawford.

No one is known to have contracted the disease in the United States. The disease has turned up in two people who lived in the U.S., but it's believed they were infected in the United Kingdom during an outbreak there in the 1980s and 1990s.

The U.S. has found two cases of mad cow disease in cows. Since the first case, confirmed in December 2003 in a Canadian-born cow in Washington state, the government has tested more than half a million of the nation's 95 million cows. The second case was confirmed last June in a Texas-born cow.

"While this surveillance has not uncovered an epidemic, it does not clear the U.S. cattle herd from infection," the researchers said.

The primary firewall against mad cow disease is a ban on using cattle remains in cattle feed, which the U.S. put in place in 1997. However, the feed ban has loopholes that create potential pathways for mad cow disease. For example, using restaurant plate waste is allowed in cattle feed.

The Food and Drug Administration proposed in October to tighten the rules, but critics said glaring loopholes would remain.

The FDA, which regulates animal feed, accepted public comments on the proposal through last month. An agency spokeswoman said Wednesday it would be inappropriate to respond to those comments.

The critics said their biggest concern is that tissue from dead animals would be allowed in the feed chain if brains and spinal cords have been removed. Brains and spinal cords are tissues that can carry mad cow disease.

In dead cattle that had the disease, infection had spread beyond brains and spinal cords. Leaving tissue from dead cattle in the feed chain would negate FDA's attempt to strengthen its safeguards, the critics said.

The most effective safeguards, they said, would be to:

_Ban from animal feed all tissues considered "specified risk materials" by the Agriculture Department, which requires that such materials be removed from meat that people eat. This includes tissues beyond the brain and spinal cord, such as eyes or part of the small intestine.

_Ban the use of dead cattle in animal feed.

_Close loopholes allowing plate waste, poultry litter and blood to be fed back to cattle.

Within the meat industry, many say the FDA proposal is effective, although some companies contend new rules are unneeded. The American Meat Institute Foundation, which represents meat processing companies, backs the FDA proposal.

"To take out the most potentially infected material, and that would be brains and spinal cords, that removes about 90 percent of the potential infectivity that is in an animal - if it's infected," said Jim Hodges, AMI Foundation president.

Mad cow disease is the common name for bovine spongiform encephalopathy, or BSE, a degenerative nerve disease in cattle.